Filter Assembly

ABSTRACT

Filter assembly for a liquid medium comprising a two-piece filter housing having a first and a second housing part with a first and second end wall respectively, surrounded by a circumferential wall, said housing parts accommodating in the space defined between the end walls three layers of filter material, and with a spacer in-between having an open structure with upstanding ribs defining chambers there between and having two end planes which define abutment planes for two layers of filter material and with a passage crosswise to the plane thereof, and with between the second layer of filter material and the second end wall a third layer of filter material, in which all three layers of filter material are discrete layers, the space between the third layer of filter material and the second end wall, and the chambers in the spacer, being in connection to the filter outlet, and the space between the first layer of filter material and the first end wall being connected to the filter inlet.

The invention relates to a filter assembly for a liquid medium such as described in the preamble of claim 1.

Such a filter assembly is known from US 2012/0012517 A.

In this known filter assembly the second and the third layer of filter material are constituted by the opposite walls of a flat rectangular sac of filter material of which the folding edge lies, together with one end of the spacer, at a distance from the neighbouring housing wall. Thus the second and the third filtering layer consist of the same material while the dimension of this sac perpendicular to the folding edge is, together with same of the spacer, smaller than the dimension of the housing in this direction.

The invention aims to improve this known filter assembly and more particularly to provide a filter assembly in which the dimensions of the filter housing are used optimally and a structure is obtained which is not only highly shock-resistant and which can operate with relatively high pressures but in which the designer has complete freedom in the choice of the material of the respective layers. Furthermore it is aimed to provide a filter assembly in which an optimal filtering is obtained with only a limited pressure drop across the layers of filter material and in which various layers with mutually different filter density can be used so that this filter is very flexible as to its practical use and can be adapted in a simple way to any specific use.

To this end the invention proposes a filter assembly such as defined in the main claim.

Preferred embodiments of this filter assembly are described in the sub-claims.

The invention is elucidated on the hand of the drawing. Therein show:

FIG. 1 a partly cut-away end view of a preferred embodiment of the assembly according to the invention;

FIG. 2 a perspective upper view of the spacer, used therein;

FIG. 3 a cut-away end view and, more detailed, the connection between the end edges of the two house parts.

In FIG. 1 the filter assembly is in its whole denoted with reference numeral 2. It comprises a filter housing which is made up of a first, lower, house part 4 and the second house part 6, which is fixed thereto. The first, lower, house part 4 has an end wall 8 and a circumferential edge 10 which merge in a outwardly directed end flange 12 which also ends in an upstanding circumferential edge 14; the second housing part 6 has an upstanding circumferential edge 16 which ends in an outwardly directed end flange 18. Vide also FIG. 3.

The first housing part 4 carries a schematically indicated filter inlet 20 which ends in the end wall 8 and the second housing part 6 carries a filter outlet 22—details of these parts will be given below.

Within the filter assembly there is a spacer 24 which is in more detail shown in FIG. 2. This spacer has an enlarged circumferential rim 26 with the long sides 28 a, 28 b and the short sides 30 a, 30 b. Between the short sides 30 a, 30 b runs a number of upstanding longitudinal ribs 32 a . . . 32 g which are parallel to the long sides 28 a, 28 b. In the middle of this spacer 24 there is an upstanding ring 34 with a central opening 36; this ring interrupts the upstanding rib 32 d and is connected with the ribs 32 c and 32 e which are next thereto.

Each of the ribs 32 a . . . 32 g is provided with a range of cut-outs 38. It is clear that the chambers 35 a . . . 35 g defined between the ribs 32 a . . . 32 g are mutually interconnected via these cut-outs 38.

In each of the short end sides 30 a, 30 b there is an opening 40 a, 40 b respectively and via these openings the chamber 35 a . . . 35 g between the ribs are interconnected with the surroundings of the spacer 24.

The lower edges 40 a . . . 40 g of the ribs 32 a . . . 32 g lie in one plane and the upper edges 42 a . . . 42 g lie also in one plane; both these planes define abutment planes for a respective layer of filter material—vide FIG. 1.

FIG. 1 shows how this, lower, abutment plane, not indicated with a reference numeral and constituted by the lower edges of the ribs 40 a . . . 40 g is an abutment plane for the first layer of filter material 46 while the upper edges 42 a . . . 42 g of these ribs constitute an abutment plane for the second layer of filter material which is indicated with 48. FIG. 1 shows how there is a third layer of filter material, indicated with reference numeral 50, and lying at a distance above the second layer of filter material 48. This third layer of filter material 50 is supported during operation by ribs 52 which protrude from the inner side of the second housing wall 6. Between these ribs 52 there are in-between spaces so that the filtered medium can freely circulate in the space above the third filter material layer 50.

Two retaining rings 35 a, 35 b, each one having an L-shaped cross-section, fit closely on the respective ends of the ring 34; they each enclose with their end edge the filter material 46 and 48 respectively. From the upper ring 35 b extends a number of radial thin arms 37 which each carry a spacer 39 supporting the third layer of filter material 50.

As particularly FIGS. 1 and 2 show the chambers 35 between the ribs 32 a . . . 32 g with the space 54 above the third filter material 50 are connected with the filter outlet 22—the passage 40 b gives a direct connection and the passage 40 a gives a connection via the space 54.

The user is fully free in his choice of the filter material for the first, second and third layer respectively; it is for instance possible that one uses for the first filter layer 46 a material with a high filter density and for the second and third layers 48 and 50 respectively a material with a lower filter density, thus a more coarse filter material.

The circumferential edges of the three layers of filter material 46, 48 and 50 are sealed with respect to each other so that the medium to be filtered (generally oil) which enters via the inlet 20 and then reaches the space 49 beneath the first layer of filter material 46 can choose between the following paths:

a. from the space 49 through the filter material 46 directly to the chambers 35 between the ribs 32 a . . . 32 g and from there via the outlet passage 40 b to the outlet 22;

b. via the central passage 36 to the space 5 a between the filter layer 48 a on the one hand and the filter layer 50 on the other end and from there:

either via the filter layer 48 to the above-mentioned chambers 35 and from there to the outlet 22 or

via the filter layer 50 to the chambers 54 and from there to the outlet 22.

As there are four different current paths in combination with the possibility to influence the choice there between by the choice of the three used filter materials properties, to be chosen at will, in combination with the configuration of the spacer the user can realize various filter properties so that for each use an optimal filter can be designed.

FIG. 3 shows in detail the way in which the first housing part 4 and the second housing part 6 are preferably interconnected. The upstanding end edge 14 of the first housing part 4 encloses the flange 18 of the second housing part 6 and these parts are at the position of the point-shaped enlargement 64 on the flange 12 interconnected by means of vibration welding. During this operation the first layer of filter material 46 is pushed inwardly namely in that part which is indicated in the drawing by hatching. In this way is ensured that waste, which is produced by the welding, can never reach the “clean” zone of the filter so that pollution of already filtered oil is impossible. However it will be clear that other ways of interconnecting the housing parts, such as gluing and High Frequency welding can also be used. 

1. Filter assembly for a liquid medium comprising a filter housing made-up from a first and a second housing part, each part having a first and second end wall respectively, surrounded by a circumferential wall, which housing parts in combination surround in the space defined by the end walls three layers of filter material, and having further an outlet and an inlet for the medium to be filtered, and comprising within this space a spacer element with an open structure and upstanding ribs between which chambers are defined, interconnected via cut-outs in these ribs, in which the respective end edges of the ribs define a first and a second end plane, which first end plane defines a (first) abutment plane for a first layer of filter material and which second end plane defines a (second) abutment plane for a second layer of filter material a fluid passage being provided through this spacer and the layers of filter material, crossing the respective main planes thereof, a first layer of filter material lying between the first abutment plane and the first end wall, a second layer of filter material lying between the second abutment plane and the second end wall, and with between the second layer of filter material and the second end wall a third layer of filter material while the space between the third layer of filter material and the second end wall, and the chambers in the spacer, are in connection with the outlet of the filter and the space between the first layer of filter material and the first end wall is connected to the filter inlet, wherein the spacer element extends across the entire inner space of the filter housing and the respective second and third layers of filter material each constitute a discrete, independent layer of which the respective end edges are sealingly interconnected and which second and third layer extend, together with the spacer element, across the entire inner space of the filter housing.
 2. The assembly according to claim 1, wherein the circumferential wall of the first housing part merges in a first, outwardly directed end flange which merges in an upstanding circumferential edge, the circumferential wall of the second housing part merges in the second, also outwardly directed end flange which lies within this upstanding circumferential edge, the first layer of filter material extends to between the first and the second end flange and these end flanges are interconnected by welding.
 3. The assembly according to claim 1, wherein said filter layers have mutually different filter densities of which the density the first filter layer has the highest value.
 4. The assembly according to claim 1, wherein spacers are accommodated between the second and the third layer of filter material.
 5. A filter assembly for a liquid medium comprising a filter housing made-up from a first and a second housing part, each part having a first and second end wall respectively, surrounded by a circumferential wall, which housing parts in combination surround in the space defined by the end walls three layers of filter material, and having further an outlet and a filter inlet for the medium to be filtered, and comprising within this space a spacer element with an open structure and upstanding ribs between which chambers are defined, interconnected via cut-outs in these ribs; wherein the respective end edges of the ribs define a first and a second end plane, which first end plane defines a first abutment plane for a first layer of filter material and which second end plane defines a second abutment plane for a second layer of filter material; wherein between the second layer of filter material and the second end wall is a third layer of filter material; and wherein the spacer element extends across the entire inner space of the filter housing and the respective second and third layers of filter material each constitute a discrete, independent layer of which the respective end edges are sealingly interconnected and which second and third layers of filter material extend, together with the spacer element, across the entire inner space of the filter housing.
 6. The filter assembly according to claim 5, wherein a fluid passage is provided through this spacer and the layers of filter material, crossing the respective main planes thereof; wherein a first layer of filter material lies between the first abutment plane and the first end wall; wherein a second layer of filter material lies between the second abutment plane and the second end wall; wherein the space between the third layer of filter material and the second end wall, and the chambers in the spacer, are in connection with the outlet of the filter; and wherein the space between the first layer of filter material and the first end wall is connected to the filter inlet.
 7. The assembly according to claim 6, wherein the circumferential wall of the first housing part merges in a first, outwardly directed end flange which merges in an upstanding circumferential edge, the circumferential wall of the second housing part merges in the second, also outwardly directed end flange which lies within this upstanding circumferential edge, the first layer of filter material extends to between the first and the second end flange and these end flanges are interconnected by welding.
 8. The assembly according to claim 7, wherein the filter layers have mutually different filter densities of which the density the first filter layer has the highest value.
 9. The assembly according to claim 8, wherein spacers are accommodated between the second and the third layer of filter material. 